Calcium carbonate synthesis experiment device capable of controlling pH

Abstract

The invention provides a calcium carbonate synthesis experiment device capable of controlling pH. A reaction unit is arranged in a constant temperature box; the sample reaction unit comprises a constant-temperature heating type digital display magnetic stirrer and a reaction container; the reaction container is filled with a reaction solution and a magnetic stirrer, and the reaction solution is used for simulating seawater components; the pumping unit comprises an automatic injection pump with two independent channels and is used for continuously inputting sodium carbonate and calcium chloride solutions into the reaction solution at a stable speed so as to induce precipitation of calcium carbonate; the pH titration unit comprises an automatic potentiometric titrator and is used for monitoring pH and temperature in real time, a titration solution is composed of sodium hydroxide or hydrochloric acid, sodium hydroxide or hydrochloric acid is automatically dropped into a reaction solution, and the pH of the calcium carbonate in the reaction container in the precipitation process is kept stable. According to the present invention, the pH real-time in-situ monitoring during the calcium carbonate precipitation process can be achieved, the corresponding titration program is started according to the experiment setting so as to ensure the pH stability during the calcium carbonate synthesis experiment process, and the characteristics of simple operation and process visualization are provided.

Description

Technical Field

[0001] The invention relates to a calcium carbonate synthesis experimental device for controlling pH, belonging to an instrument used in the field of experimental geochemistry and carbonate rock sedimentology research. Technical Background

[0002] Carbonate rocks are widely distributed in the geological history and are a good carrier for studying ancient marine chemistry and redox conditions. The prerequisite for accurately interpreting the element and isotope geochemical signals recorded in calcium carbonate sediments in the geological history is to understand the element distribution and isotope fractionation behavior of the calcium carbonate formation process. As an important parameter of solution chemistry, pH may affect the type of elements in the solution, and then affect the element distribution behavior and isotope fractionation behavior in calcium carbonate minerals. At present, some studies have studied the element and isotope behavior of the calcium carbonate formation process by conducting indoor synthesis experiments. However, the existing technology mostly maintains pH by introducing CO2 gas. This method has the disadvantages of complex operation, lack of intelligence, and difficulty in maintaining pH at the experimental target value. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a calcium carbonate synthesis experimental device for controlling pH. The device can not only record the pH of a reaction solution in real time in situ, but also automatically drip sodium hydroxide or hydrochloric acid according to the pH of the solution to stably maintain the pH of the reaction solution. The device has the characteristics of simple operation, intelligent control and visualized results.

[0004] A pH-controlled calcium carbonate synthesis experimental device comprises a sample reaction unit, a pumping unit, and a pH titration unit; the reaction unit is arranged in a constant temperature box;

[0005] The sample reaction unit comprises a constant temperature heating type digital display magnetic stirrer and a reaction container; the reaction container is filled with a reaction solution composed of sodium chloride, calcium chloride, magnesium chloride, and sodium carbonate and a magnetic stirrer, and the reaction solution is used to simulate the composition of seawater; the reaction container is placed on the constant temperature heating type digital display magnetic stirrer;

[0006] The pumping unit includes two independent channel automatic syringe pumps for continuously inputting sodium carbonate and calcium chloride solutions into the reaction solution at a stable rate to induce the precipitation of calcium carbonate;

[0007] The pH titration unit comprises an automatic potentiometric titrator, a temperature electrode, a pH glass electrode and a pH reference electrode of the automatic potentiometric titrator are inserted into the reaction solution of the reaction container through a side opening of the thermostat to monitor the pH and temperature in real time. The titrant on the automatic potentiometric titrator is composed of sodium hydroxide or hydrochloric acid. According to specific experimental requirements, the dripping speed of the sodium hydroxide or hydrochloric acid is set to automatically drip into the reaction solution so that the pH in the reaction container during the precipitation of calcium carbonate is kept stable.

[0008] Further:

[0009] The constant temperature heating digital display magnetic stirrer is provided with a temperature regulator, a temperature display screen, a speed regulator and a speed display screen; and is used to achieve uniform mixing of the reaction solution and maintain temperature stability.

[0010] The pumping unit comprises a first syringe filled with a sodium carbonate solution and a second syringe filled with a calcium chloride solution. The first syringe and the second syringe are both placed on an automatic injection pump host and fixed by a syringe fixing clamp. The first syringe is connected to a sodium carbonate solution pumping tube, and the second syringe is connected to a calcium chloride solution pumping tube. The ends of the sodium carbonate solution pumping tube and the calcium chloride solution pumping tube are respectively suspended on the reaction solution in the reaction container through side openings of a thermostatic box. The automatic injection pump host is provided with a solution pumping speed and time regulator.

[0011] The pH titration unit comprises an automatic potentiometric titrator, a sodium hydroxide titration bottle and a hydrochloric acid titration bottle are respectively placed on the automatic potentiometric titrator, a sodium hydroxide reserve solution bottle is connected with the sodium hydroxide titration bottle through a sodium hydroxide inlet pipe, a hydrochloric acid reserve solution bottle is connected with the hydrochloric acid titration bottle through a hydrochloric acid inlet pipe, a sodium hydroxide discharge pipe and a hydrochloric acid discharge pipe are suspended on a reaction solution in a reaction container through a side opening of a thermostat; a temperature electrode, a pH glass electrode and a pH reference electrode of the automatic potentiometric titrator are inserted into the reaction solution in the reaction container through the side opening of the thermostat.

[0012] Two 50ml syringes in the pumping unit are filled with calcium chloride solution and sodium carbonate solution respectively and placed on an automatic injection pump. A PVC plastic hose is connected to the syringe needle. The hose is finally suspended above the reaction solution through an opening on the side of the thermostat to continuously pump calcium chloride solution and sodium carbonate solution into the reaction solution, thereby promoting the precipitation of calcium carbonate; the pH titration unit is composed of a set of automatic potentiometric titrators, and the main unit is placed outside the thermostat. The pH reference electrode, glass electrode, and temperature electrode all enter the thermostat through openings on the side of the thermostat and are directly inserted into the reaction solution to monitor the pH of the reaction solution in real time. The automatic potentiometric titrator contains two sets of titration pipelines, and the liquid inlet pipes of the two sets of titration pipelines are respectively inserted into PP material and 1L plastic bottles filled with sodium hydroxide and hydrochloric acid solutions. Therefore, the titrants of the two sets of titration pipelines are sodium hydroxide and hydrochloric acid, respectively. The discharge pipe of the titration pipeline is also suspended above the reaction solution through the side opening of the constant temperature box. According to the target pH set in the specific experiment and the real-time monitored solution pH, sodium hydroxide or hydrochloric acid solution can be automatically dripped to ensure the pH stability of the reaction solution and continuously record the pH during the entire experimental cycle.

[0013] It can be seen from the above technical scheme that the pH-controlled calcium carbonate synthesis experimental device provided by the present invention includes a sample reaction unit, a pumping unit, and a pH titration unit. The experimental equipment used in each unit has the characteristics of simple operation, high intelligence, and high efficiency. The device can synthesize calcium carbonate under stable pH conditions, providing a basic theory for exploring the element and isotope behavior in the calcium carbonate formation process, and providing support for interpreting the sedimentary geochemical behavior of calcium carbonate sediments in the geological history period. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the calcium carbonate synthesis experimental device for controlling pH of the present invention;

[0015] In the figure, 1, reaction vessel; 2, constant temperature heating type digital display magnetic stirrer; 3, temperature regulator; 4, temperature display screen; 5, speed regulator; 6, speed display screen; 7, syringe fixing clamp; 8, automatic injection pump host; 9, first syringe; 10, second syringe; 11, solution pumping speed and time regulator; 12, sodium carbonate solution pumping tube; 13, calcium chloride solution pumping tube; 14, sodium hydroxide reserve solution bottle; 15, hydrochloric acid reserve solution bottle; 16, sodium hydroxide titration solution bottle; 17, hydrochloric acid titration solution bottle; 18, sodium hydroxide inlet tube; 19, sodium hydroxide discharge tube; 20, hydrochloric acid inlet tube; 21, hydrochloric acid discharge tube; 22, automatic potentiometric titrator; 23, temperature electrode; 24, pH glass electrode; 25, pH reference electrode; 26, constant temperature box. DETAILED DESCRIPTION

[0016] The pH-controlled calcium carbonate synthesis experimental device provided by the present invention comprises a sample reaction unit, a pumping unit, and a pH titration unit; the reaction unit is arranged in a thermostatic box 26;

[0017] The sample reaction unit comprises a constant temperature heating type digital display magnetic stirrer 2 and a reaction container 1, wherein the reaction container 1 is filled with a reaction solution composed of sodium chloride, calcium chloride, magnesium chloride, and sodium carbonate and a magnetic stirrer, wherein the reaction solution is used to simulate the composition of seawater; the reaction container 1 is placed on the constant temperature heating type digital display magnetic stirrer 2; the constant temperature heating type digital display magnetic stirrer 2 is provided with a temperature regulator 3, a temperature display screen 4, a speed regulator 5, and a speed display screen 6;

[0018] The pumping unit includes a first syringe 9 filled with sodium carbonate solution and a second syringe 10 filled with calcium chloride solution. The first syringe 9 and the second syringe 10 are both placed on the automatic injection pump host 8 and fixed by a syringe fixing clamp 7. The first syringe 9 is connected to a sodium carbonate solution pumping tube 12, and the second syringe 10 is connected to a calcium chloride solution pumping tube 13. The ends of the sodium carbonate solution pumping tube 12 and the calcium chloride solution pumping tube 13 are respectively suspended on the reaction solution of the reaction container 1 through the side openings of the thermostat 26; the automatic injection pump host 8 is provided with a solution pumping speed and time regulator 11;

[0019] The pH titration unit includes an automatic potentiometric titrator 22, a sodium hydroxide titration bottle 16 and a hydrochloric acid titration bottle 17 are respectively placed on the automatic potentiometric titrator 22, a sodium hydroxide stock solution bottle 14 is connected to the sodium hydroxide titration bottle 16 through a sodium hydroxide inlet pipe 18, a hydrochloric acid stock solution bottle 15 is connected to the hydrochloric acid titration bottle 17 through a hydrochloric acid inlet pipe 20, a sodium hydroxide discharge pipe 19 and a hydrochloric acid discharge pipe 21 are suspended above the reaction solution of the reaction container 1 through a side opening of a thermostat 26; a temperature electrode 23, a pH glass electrode 24, and a pH reference electrode 25 of the automatic potentiometric titrator 22 are inserted into the reaction solution of the reaction container 1 through a side opening of the thermostat 26.

[0020] The working process of the pH-controlled calcium carbonate synthesis experimental device provided by the present invention is as follows:

[0021] Put the prepared sodium chloride, calcium chloride, magnesium chloride and sodium carbonate solution into the reaction vessel 1, and set the temperature regulator 3 and the speed regulator 6 according to the actual experimental requirements;

[0022] Prepare sodium carbonate solution and calcium chloride solution and add them into the first syringe 9 and the second syringe 10 respectively, and set the corresponding pumping speed and pumping time through the solution pumping speed and time regulator;

[0023] Insert the temperature electrode 23, the pH glass electrode 24, and the pH reference electrode 25 into the reaction solution to monitor the pH of the solution in real time in situ, prepare sodium hydroxide and hydrochloric acid solutions and add them into the sodium hydroxide stock solution bottle 14 and the hydrochloric acid stock solution bottle 15 respectively, start the automatic potentiometric titrator 22, the sodium hydroxide stock solution enters the sodium hydroxide titration bottle 16 along the sodium hydroxide inlet pipe 18, and then automatically drips into the reaction solution along the sodium oxide discharge pipe 19 according to the difference between the reaction solution and the experimental target pH to maintain pH stability; the hydrochloric acid stock solution enters the hydrochloric acid titration bottle 17 along the hydrochloric acid inlet pipe 20, and automatically drips into the reaction solution along the hydrochloric acid discharge pipe 21 according to the difference between the reaction solution and the experimental target pH to maintain pH stability.

[0024] During the whole experiment, the continuously pumped sodium carbonate solution and calcium chloride solution caused the reaction solution to reach saturation with respect to calcium carbonate, resulting in the precipitation of calcium carbonate; while the sodium hydroxide titration solution and the hydrochloric acid titration solution jointly maintained the pH stability of the reaction solution. After the experiment, the synthesized calcium carbonate and the solution were separated by a sand core filter, and finally the calcium carbonate product synthesized under stable pH conditions was obtained.

Claims

1. A calcium carbonate synthesis experimental device for controlling pH, characterized in that: It includes a sample reaction unit, a pumping unit, and a pH titration unit; the reaction unit is arranged in a constant temperature box (26); The sample reaction unit comprises a reaction container (1) and a constant temperature heating type digital display magnetic stirrer (2); the reaction container (1) is filled with a reaction solution composed of sodium chloride, calcium chloride, magnesium chloride and sodium carbonate and a magnetic stirrer, and the reaction solution is used to simulate the composition of seawater; the reaction container (1) is placed on the constant temperature heating type digital display magnetic stirrer (2); The pumping unit includes two independent channel automatic syringe pumps for continuously inputting sodium carbonate and calcium chloride solutions into the reaction solution at a stable rate to induce the precipitation of calcium carbonate; The pH titration unit comprises an automatic potentiometric titrator (22), wherein a temperature electrode (23), a pH glass electrode (24), and a pH reference electrode (25) of the automatic potentiometric titrator (22) are inserted into the reaction solution of the reaction container (1) through a side opening of a thermostat (26) to monitor pH and temperature in real time. The titrant on the automatic potentiometric titrator (22) is composed of sodium hydroxide or hydrochloric acid. According to specific experimental requirements, the dripping speed of the sodium hydroxide or hydrochloric acid is set to automatically drip into the reaction solution so that the pH in the reaction container (1) during the precipitation of calcium carbonate is kept stable.

2. The calcium carbonate synthesis experimental device for controlling pH according to claim 1, characterized in that: The constant temperature heating digital display magnetic stirrer (2) is provided with a temperature regulator (3), a temperature display screen (4), a speed regulator (5), and a speed display screen (6); and is used to achieve uniform mixing of the reaction solution and maintain temperature stability.

3. The calcium carbonate synthesis experimental device for controlling pH according to claim 1, characterized in that: The pumping unit comprises a first syringe (9) filled with a sodium carbonate solution and a second syringe (10) filled with a calcium chloride solution. The first syringe (9) and the second syringe (10) are both placed on an automatic syringe pump host (8) and fixed by a syringe fixing clamp (7). The first syringe (9) is connected to a sodium carbonate solution pumping tube (12), and the second syringe (10) is connected to a calcium chloride solution pumping tube (13). The ends of the sodium carbonate solution pumping tube (12) and the calcium chloride solution pumping tube (13) are respectively suspended on the reaction solution in the reaction container (1) through side openings of a thermostatic box (26). The automatic syringe pump host (8) is provided with a regulator (11) for solution pumping speed and time.

4. The calcium carbonate synthesis experimental device for controlling pH according to claim 1, characterized in that: The pH titration unit comprises an automatic potentiometric titrator (22), a sodium hydroxide titration bottle (16) and a hydrochloric acid titration bottle (17) are respectively placed on the automatic potentiometric titrator (22), a sodium hydroxide stock solution bottle (14) is connected to the sodium hydroxide titration bottle (16) via a sodium hydroxide inlet pipe (18), a hydrochloric acid stock solution bottle (15) is connected to the hydrochloric acid titration bottle (17) via a hydrochloric acid inlet pipe (20), a sodium hydroxide discharge pipe (19) and a hydrochloric acid discharge pipe (21) are suspended on the reaction solution of the reaction container (1) through a side opening of a thermostat (26); and a temperature electrode (23), a pH glass electrode (24) and a pH reference electrode (25) of the automatic potentiometric titrator (22) are inserted into the reaction solution of the reaction container (1) through a side opening of the thermostat (26).

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